Solid state nuclear track detectors have become an important tool in every investigation of radon levels in the surrounding environment. In the present work radon concentration and radon exhalation rate were measured using an alpha track detector (LR-115 type II) in forty three samples of different types of granite rocks were collected from Um Ara, South Eastern Desert, Egypt. From the obtained results the average values of radon concentrations for Western Trenches ranged from 4051.67 ± 98.87 to 16396.15 ± 154.54 Bqm-3 and the average values of radon concentration varied from 4638.68 ± 82.54 to 13381.30 ± 174.65 Bqm-3 for the Eastern Trenches. The obtained results show that the radon concentrations of the samples are higher than the recommended world limit of ICRP. The present study is important to detect any change in radioactivity background level in the studied area and to establish a data base for granite rocks.
